The alternative title for this post was “I’m hungry; you’re wrong.” I’m not sure which is better… In any case, consider this bit from Kahneman:

Resisting this large collection of potential availability biases is possible, but tiresome. You must make the effort to reconsider your intuitions… Maintaining one’s vigilance against biases is a chore — but the chance to avoid a costly mistake is sometimes worth the effort.

Now as I understand it, this is basically a function of self-control. By taxing your brain to counteract biases, you’re drawing on a finite pool of mental energy. We know from studies of willpower that doing so can cause problems. As John Tierney reported in an excellent NYT Magazine piece on decision fatigue:

Decision fatigue helps explain why ordinarily sensible people get angry at colleagues and families, splurge on clothes, buy junk food at the supermarket and can’t resist the dealer’s offer to rustproof their new car. No matter how rational and high-minded you try to be, you can’t make decision after decision without paying a biological price. It’s different from ordinary physical fatigue — you’re not consciously aware of being tired — but you’re low on mental energy.

He also relates a fascinating study of Israeli parole hearings:

There was a pattern to the parole board’s decisions, but it wasn’t related to the men’s ethnic backgrounds, crimes or sentences. It was all about timing, as researchers discovered by analyzing more than 1,100 decisions over the course of a year. Judges, who would hear the prisoners’ appeals and then get advice from the other members of the board, approved parole in about a third of the cases, but the probability of being paroled fluctuated wildly throughout the day. Prisoners who appeared early in the morning received parole about 70 percent of the time, while those who appeared late in the day were paroled less than 10 percent of the time.

It gets more interesting:

As the body uses up glucose, it looks for a quick way to replenish the fuel, leading to a craving for sugar… The benefits of glucose were unmistakable in the study of the Israeli parole board. In midmorning, usually a little before 10:30, the parole board would take a break, and the judges would be served a sandwich and a piece of fruit. The prisoners who appeared just before the break had only about a 20 percent chance of getting parole, but the ones appearing right after had around a 65 percent chance. The odds dropped again as the morning wore on, and prisoners really didn’t want to appear just before lunch: the chance of getting parole at that time was only 10 percent. After lunch it soared up to 60 percent, but only briefly.

So, returning to the Kahneman bit, I wonder if we might observe a similar phenomenon with respect to political bloggers. Would ad hominem attacks follow the same pattern throughout the day? Might bloggers who had just eaten have the mental energy to counter their biases, to treat opponents with respect, etc.? And might that ability be depleted as the time between meals wears on and their mental energy is lowered? This could be tested pretty easily by analyzing the frequency of certain ad hominem clues like, say, the use of the word “idiot”, and then checking frequency against time of day. I’d love to see this data, and not just because I want an excuse to snack while I write.